[ff3d-users] line 26: syntax error "prism"

[Karl Hauschild]

Hi,

My reason for wanting to use freeFEM3D is to determine the
electric field within a segmented Germanium detector shaped
roughly like that gievn in det_sym.jpeg and agata_view.png.
A further complication would be to round of the surfaces.
I thought that a linear spline + little spheres pulled out
via prism would do the trick. But to start with I just used
a conic sweep of a linear spline.

Unfortunately ff3d does not seem to like the generation of solids
using the "prism" mechanism. Does anyone have any other suggestions ?

> ff3d agata.ff
     Parsing the file 
......................................................
......................................................
.......................................................
..................... done
      Treating data
      Building Scene ... done
      line 26: syntax error "prism"


In POV-Ray the code is :
difference {

  intersection {
    prism {
      conic_sweep
      linear_spline
       0.625, // sweep the following shape from here ...
       1, // ... up through here
       7, // the number of points making up the shape ...
       < 24.43,-42.32>, < 48.87,0>, < 24.43, 42.32>,
       <-24.43, 42.32>, <-48.87,0>, <-24.43,-42.32>,
       < 24.43,-42.32>
      scale <1, 240, 1>    //make it 240 mm long
      rotate <180, 0, 0>   //point upwards
      translate <0,240,0>  //place base at 0
    }
    //use cylinder intersection
    cylinder {<0,-0.01,0>,<0,90.01,0>,40}

    //assign a label to the outer surface
    pigment {color rgb <0,1,0> }
  }

  //subtract out the core...
  cylinder {<0,-0.1,0>,<0,75.1,0>,5
    //assign a label to the inner core
    pigment {color rgb <0,0,1> }
  }
}

Cheers,

Karl

==================================================================
In case it helps : In Geant4 I have used : the intersection of a
polyhedra and a cylinder.